Many different kinds of spouts have been proposed over the years for use during a gravity transfer of liquids from a container into a receptacle, such receptacle being for instance another container or a tank, to name just a few examples. Some of these spouts include an air vent to admit air inside the container through the spouts when the liquid flows, and also a shutoff valve to control the liquid flow during the transfer. Examples can be found, for instance, in U.S. Pat. Nos. 8,403,185 and 8,561,858.
While most of the prior arrangements have been generally useful and convenient on different aspects, there are still some limitations and challenges remaining in this technical area for which further improvements would be highly desirable.